Rotary cutter



3. 1 7 n 4v Li N @a .M i@ 3, w 2 m T rw h W 9 uw mw/ OQI/M I TPM N y v s W z N/e M j r n T I M m w 0r K Y E. m JA c. m n S w a .1 4%/ .asf 9 ..1 nf/ m ,i 3 lv? 4 Nov, 9, 1943. c. 4E. KRAus ROTARY CUTTER Fi 1ed Jan. '16, 1942 v s sheets-sheet 2 NV E'NTQLJ @hcw/e5 E Wadi Patented Nov. 9, 1943 UNITED [STATES PATENT OFFICE ROTARY CUTTER Charles E. Kraus, Rochester, Y. Application January 16, 1942, YSerial No. 427,Il38

t 13 Claims. (orga- 105) This invention relates to multiple toothed cutters of the type employed for performing a socalled face milling operation.

The general object is to produce a substantial increase in the rate at which smooth surfaces may `be formed by such cutters without atthe same time increasing their cost of construction or maintenance in service.

In conventional face milling cutters, no attempt is made to control the flow of chips. Some are thrown under theV cutter between the work surface andthe cutter while others are carried around between adjacent teeth. This reduces the service life of the cutter and necessitates wide spacing of the teeth inr order to avoid clogging with a consequent reduction in permissible rate of feed. A

A more detailed object therefore is to'provide a face milling cutter in which control of the chip flow is so complete and positive that the spacing of the cutter teeth may be reduced materially and the permissible rate of feed thus increased correspondingly.

Another object is to provide a cutter in which the cutter body and the side walls of the adjacent teeth coact in a novel way to provide effective guiding and disposal of the chips.

The invention also resides in the novel arrangement cf the blades in the cutter body to insure proper rigidity of the blade mounting in spite of the close spacing of the blades.

Still another object is to provide a novel mounting for the cutter blades which coacts with the blade shape and arrangement to provide for efective locking, most efficient use of the cutting material, optimum range of adjustability, and ease of sharpening.

A further object is to control the vibration producing tendency incident to the cutting action.

Other objects and advantages of the inven tion will become apparent from the following detailed description taken in connection with the accompanying drawings, in which n Figure 1 is an elevational view of a cutter embodying the present invention, a portion being shown in section along the line I-I of Fig. 2.

Fig. 2 is a fragmentary perspective View show ing the arrangement of the cutter blades, the serrations thereon being omitted.

Fig. 3 is a fragmentary diametrical sectional view of the cutter showing a different blade than the one shown in the sectioned part of Fig. l, the section being along the line 31-3 of Fig. 2.

'.Fig.,` 4 isa fragmentary end view.

cutting edges.

Figs. 5 and 6 are fragmentary sectional views takenV respectively along the lines 5-5 and Ii--B of Fig. 4. A

Fig. '1 is a perspective plan view illustrating the action. of the cutter teeth on a workpiece.

Fig. 8 is a fragmentary perspective view illus-V trating the blade locks. t

Fig. 9 is an elevational viewof a blade and its locking wedge. l y M Fig. 10 Vis a section Vtaken along the Vline Ill-Il) of Fig. 5. l

For purposesof illustration, 'the embodied in a so-called inserted blade cutter for removing va layer a of metal from a work piece II to form a smooth surfacerIZ during relative feeding'of the workand cutter along the surface while the cutter is rotating clockwise. It is to be understood that I do not intendto limit the invention by-such exemplary disclosure but aim to cover al1 modifications, alternative constructions, and uses falling within thelspirit and scope-of the invention as expressed inthe ap-v pended claims.

The cutter comprises an annular seriesof teeth I3 constituting the ends-off-blades yor bars I4 and I4' of cutting material and projecting from one end of a body I5 which in this instance is a single lringlike forging. The latter `may beV fastened in any suitableway to the end of a power driven spindle. (not` shown) projected throughsJ central recess I6 in the body.

Each-tooth I3 has a main or side cutting edge I1 and' an end or finishing edge I8 both disposed in the plane of the leading or 'cutting face I9 of the tooth. Surfaces 26 and 2l are ground on the end of .the tooth toprovide' proper relief for the In accordance with the present invention, the cutting faces I9 of eachtooth and a rear surface on the preceding tooth coact to provide a passage 22 diverging inwardly and 'radially between the work surface I2 and the end face 23 of the body I5. .This passage is so positioned and shaped as to receive they chips 24 formed by the cutting edges I1 and guide the samepositively in a well deiinedpath toward the center. of the cutter until they pass the work.

To form `such a passage without sacrificing tooth strength, the teeth I3` are made generally triangularl in cross-section having side surfaces 25 and 26 intersecting each other and each'intersecting the other side which defines the; cutting face I9. Y Herein, a substantially equilateralshapeVv is employed with Vthe'side 25 facing outwardradially with its trailing vedge 21 disposed-Tat a shorter radius than the cutting edge Il so as to invention is provide proper clearance for the latter. The sides I9 and 26 of each tooth thus converge inwardly and each coacts with the other side of the next adjacent tooth to dene one of the chip passages 22 which opens inwardly and diverges quite sharply. The throat of this passage between the edge 21 of one tooth and the face I9 of the next tooth is so sized and located as to insure entry of the chips that naturally flow inwardly from the main cutting, edge Il and. then prevent escape of the chipst outwardlyl While permitting and inducing free inward flow even though the chips may take the form of spiral coils. Thus, the edge.

21 is spa-ced radially only a short distance inwardly from the cutting edge Il of theA next.

tooth. Also, it is spaced close to thecutting face I9 and thus traps the entering chips and prevents' reversal of their flow. Withthe triangular cion,- struction, the side 2G of one tooth is disposedat such a large angle relative to the face i9 I of the followingV tooth as=to allow ample space of increasing-widthforcoiling of.- the chips or accumulation of chip pieces without any possible d anger of clogging..

Tofurther. insure; effective.y disposal of` chips, theendfiace-of thefcutter. body is contoured to provide for divergence of the; chip passages axiallygof) the cutter., that is,v in .-af direction transverse to the radial divergence. This is accomplishedA by coningr;thez'outer peripheralportion 23 `of the-end face so that this surface diverges inwardly from the finished-work surface; I2 as shown in Figs. 1 and 3;, Thus,t he.chip. passages diverge inV two transverse.. directions i and` provide adequate space for;A disposaly of. the chipsl` in,- spite of the close spacing; of the teethtwhichis employed-in order,l

to trapfthezchips: and guide them positively in the proper direction; Accordingly, it is impossibleV topack on'clog the chip-cavities.

The closespaoing; off4 theteeth which is made possible: by,v the effective.r chip disposing action-` aboverdescribed; enablessthe number cf `teeth inaf.

cutter of given diameter to be increasedconsiderably as: comparedf to. conventional face milling cutters. For example,l .in;ordinary cuttersof ,the`

and: one-eighthe inches.`

an inch: maybe. used-inl thesame type of Vcutter' withanincreaselof seventy-five per cent inper-I missible feed ra'teand without any sacrifice inv I cutting eiciency or smoo-thness of nish. Similarly, inacutter of'the'extra heavy duty type, the blade pitch; may -be-.one and ve-eighths inches ascomparedxto -two and vef-eighths inches which isfthe pitch commonlyprovidediin such cutters.

The triangular blades abovel described are, o1" course, mounted: in openings'. 3D. of correspond ing.: cross-sectional. shapel annularly spaced aroundithe'ring Iii/.wand extending generallyflona various ways; means isf-preferably employed which permits all sides-offtheopenings Sand'the-sides I9 and'ZBof theblades tobe smooth', whichcoactsv withthei outwardly facing sides 25' of the 70 While'. the blades mayy berlockedin place in of the blade recesses.

blades, which permits of ready adjustment of the blades for wear, and which does not necessitate special sharpening methods. Herein, the locking means includes a wedge 33 rounded on one side to seat in a complemental groove 34 in the outer wall 35 and having transverse serrations 3S formed on its opposite side to intert with complemental serrations 31 on the side 25 of the blade. The wedge and groove taper away from the toothed end of the cutterl and the wedge thickness is suchi that in7 the lbclie'd position of tlie blade, the large end"33of'th'e wed'ge is disposed substantially flush with the beveled surface 39 of the cutter body.

Thewedge lock thus constructed and mounted in relation to the sides of the triangular blade has numerousadvantages. It permits the use of blades-ofimaximum'length and the formation of the blade recesses in the body by a simple broaching operation. The location on the outer side of the bladee does. not in .anyv way. interierewiththe spacingof. the blades, and. thelwedge functionsto force the other twosides againstthe solid .body` walls 3-I and.32. For. the samereason. vthe blade serrations` are outsideof the. chip. passages, andy do not interfere withatheow of.y chipsacross .the cutting face. or. throughthe passages. 22.`

To permit the'bladesA to r.be located. close to.- gether as. described.- above. withoutdnterference of the blades.' or. sacrificing. rigidity of their.; mountingl thefbladesare distributed arnundithe1 metal of,the.body linstaggered. relation with. the adjacent blades-disposed at different angles to the plane of notation but.- withtheractive: ends. projecting from. thefbody, at. substantially. the same radius.so.that thecutting .edgesmay be. equidistant from the axis. In this instance,.half\` of. theblades indicatedby prime, numbers are canted radially. at. an. anglel b, about. seventy de-v greesv in.A theV presentfinstance, to. the plane. of. cutter. rotation and, then tilted. circumferentiaily and reversely to.the.direetion.of.,cutter rotation through an angle c which.is,about.fo1tty.-flve. de.- grees asY indicated in. Fig.. l'. rThe remaining blades lli: are similar-ly. canted. and' 'tiltedv but at: v

angles d and. e. which. are approximately. sixty., and twenty-live. degrees respectively. as indicated. in Figs..2.and.3.. Fon apurpose to. appear later, thebladesI lfliandf M'are. also twisted relative. to. the. cutter body. about their longitudinal axes to, set the cutting, faces i9. at.. different rake4 angles f and g twelve and eightdiegrees. as, shown in Fig. 2. The result. of. this blade arrangement is; that/beginning in la. plane. slightly above the toothed face of the cuttenthe bladesections: are staggered.- asv shownx in Fig. 5 and 'overlapy each. other only slightly. The'radiallspacing `r of 'the differently inclined blades increases until. at vthe opposite endof'the cutter (seeli'ig), theblade sections I4' and 61V are divided into radially, spaced groups so that inspite of the close spacing ofth'eir active endseach blade' isseparatedirom, the others by@Y substantiarwidthjor bndymetai and thus supported? with the, proper`rigiiiity-l, By; tilting the blades I''and.' Iii"circiinrfrentiailieat then diierent angles c and' 6 any possibilityiof. interference` ci blades is avoidedandlthejblade sections-are ldisu-irnuedevenly; mme may; meter ',Ihus, as shown Fig: 5,Y thisA diierentiall tilting results' in location ofthe apex 4U. off-eachbla'de M. about midwaybetween the bases? ofLtLwoy innerbladesldl' f 1 The different'blade inclinations as a-bavedescribedare,.of' course, determinedby. the angles Thesemay beb'ro'ached creasm manillfatiirn i :Br tiltingihetblaldes pire. .fsl'gnliill/ as. abOi/ described atv twenty-five fand i forty-five "degrees to radii of the cutter; correspondingly `different shear angles are imparted to the mainwcutting edges on lthe fdifferentbladesi Thisfalternate variationin the shear anglesof successivefblades minimizes any tendency ofthe cutter tchatter due toampli'fication inorie blade of any 'vibra tion seit upV in thefprecedng' blade. This' vibra'`v tion tendency isfalso minimized vby Ithe rake angles of the" adj ace'nt blades which y differ Y due' tcifthefl differences in the fshearfangles land" also by twisting thefbl'adesas 'described above.' in spite 'ofthe' closespacing" 'of the cutter y teeth which'rdinarilyfwould be 'expected to increase vibration,"nor 'notioeable chatterA has been ob- Ifclai'rn 'as` my'inventioricf' A1. `A facefinilling cutter "for removing a 'metal layer 'fifoinaY work' piece to"frmasurfa"ce thereon by'relat'ive feeding' movement between'therotating 'cutter and work piece parallel to said surface, said"`cutter having a 'rotary "body,` anda multiplicity o'f'teethA of generally triangular crosse section spaced around the periphery ofsaid body and projecting from the'end surface thereof, the sides of adjacent'teeth and said'end surface being shaped and positioned tov define funnel shaped chip recesses each having a throat adjacent` one cutting edge and side rand topiwalls diverging inwardly and away" from such edgein planes respectively parallel' and perpendicular toy said work surface whereby to` insure inward ldeflection of the chips removed by the respectiveA cutting edges. 'i

2. .A face milling cutter for removing a metal layer from a work piecelto form a surface thereon by relative feeding movement betweenthe rotating cutter and work piece parallel to said surface, said cutter having a rotary body, a multiplicity of teeth spaced around the periphery of said bodiT and projecting from the end surface thereof, the sides of 4adiacerit ,teeth and said end surface being shaped andfpositioned to define funnel shaped chiplvrecesses each having a throat adjacent one cutting edge and side and top walls diverging inwardly and away from such edge in planes respectively parallel and perpendicular to said work surface whereby to insure inward deflection of the chips removed byfthe respective cutting edges, and said chip recesses being of such narrow Widths'at their outer ends as to prevent outward flow ofthe chips.

3. A face milling 'cutter having, in combination, a rotatable cylindrical body, a Vmultiplicity of blades of generally' triangular cross-section having ends projecting from one end of said body in a single annular series, with one side of the triangle facing outwardly, and cutting edges formed on said ends equidistant from the rotational axis of said body and each directing its chip into the inwardly diverging `passage defined by the opposed sides of the adjacent blades, said blades being mounted in said body at varying angles whereby in a plane axially spaced from said body end, the blade sections are disposed in a plurality of annular series radially spaced apart.

4. An inserted blade milling cutter having a body and two sets of blades mounted therein at different angles relative to the plane of cutter rotation and cooperating with the cutter body to form a multiplicity of chip passages with walls flaring away from the cutting edge and with and receiving the latter with said sides "facin'gl radially and outwardly,"wedges-having fo'rm'.- tions intertting with formations of the respective 'blades and shiftablewith 'the blades `longi-4 tudinally of saidopening's to lock the-blades'in said body; and cuttingedge's formed on the pro-` jecting blade 'ends adjacent' onemargin o'fsaid' sidesjth'e' i other two sides of each "blade 'being smooth fand converging inwardly so *asf to' coact with a side of the adjacentz, blade` to 'g form aninwardly' diverging 'passage 'having a constricted throat forreceiving'and trapping-inf the passagethe chips removed by." the-associated A4cutting edge 6.1fAn inserted blade cutter comprising amultii plicity of' blades .fof generally` triangular cross section substantially fthroughout their Y'lengthsr and locking formations spaced along `one side, arotatable body having smooth walled openings complementingV the cross-sectional shape of said blades and receiving the latterwith said formed sides `facing radiallyand outwardly, longitudinal grooves formedin the outer -wall'of each of saidA openings, wedges having formations intertting with formations vof the respective blades and seated in said grooves to `lock the blades inr said body, and cuttingedges formed on the projecting blade ends adjacent one-margin of saidformed sides. f '7.A face millingVV cutter having, `in combina-V tion, a rotatableV cylindrical body, a multiplicity of blades of triangular cross-sections. mounted on said body with their ends Yprojecting from one end of the body and with one sidev 'of the triangle facing outwardly, cutting edges formed on said projected fend's iat the"leadingedges thereof,' said blades being Aspaced close "together so that the sides' of adjacent projectingv 'ends form chip: passages diverging inwardlyto direct the flow of chips inwardly toward the cutter axis; and the adjacent blade'sbeingdisposed at `different angles relative to the` plane of cutter'rotation and also turned about their longitudinal axes at different angles to set thecutting edgesof successive blades for engagement with the work-at different rake and shearangles whereby to eliminate chatter of the cutter in spiterofthe-close spacingiof'the blades;

8. A milling cutter for removing a metal-layer fromv a workpiece to form a-surface thereon by relative feeding movement betweenY the rotating cutter and therworkpiece, said cutter comprising, in combination, a cylindrical body, an annular series of circumferentially spaced teeth of generally triangular cross-section projecting from the end of said body a distance suicient to permit of chip ow radially inwardly through the spaces between said work surface and said body end, one side of each tooth triangle facing outwardly while the remaining leading and trailing sides converge inwardly so that the opposed sides of adjacent'teeth define a chip passage which flares inwardly toward the cutter axis, and a side cutting edge formed on each tooth at the junction of the outwardly facing side and the leading edge thereof whereby to constitute the latter the cutting face, the latter face being positioned to induce the natural flow of chips radially inwardly tooth a distance substantially less than .thewidth of saidoutwardly facing :tooth-side so .as to -deiflne a narrow chip passage entrance for receiving the inwardly flowing chips .and trapping the same in' the passage whereby `to insure continued in ward :movement oi thel chips Y and :discharge thereof Afrein the enlarged inner end of the passage.- f v Y 9. A milling cutter for removing a metal layer from 1a workpiece to form asuriace`r thereon by rotation .of the cutter about an axis :normal to the work" surface combined with relative feeding movementy between the rotating cutter andthe workpiece .along the work surace, .said vcutter comprising, in combination, a .rotatable body,- an annular series of .circumferentially,spaced teeth projecting from the end olf said body a distance to `permit of chip flow radially and inwardly between said work surfacexand .said body end, a side on each tooth facing ontwardly and having a cutting edge along the leading edge, a cutting face on the leading side of each :toothpositioned tol induce the chips `formed by said edge to ow inwardly towardt-he cutter axis, land a third` y-' side on each tooth converging toward and merg ing withV the -cuttingface of thev tooth and cooperating with kthe cutting face of the succeeding tooth to define afchipl'passage having a narrow throat adjacent the cutting edge for receiving the chips vformed thereby and sidewalls .diverging radially inwardly from vsaid throat and' guiding the chips to ycontinue their flow inwardly between the body land the work surface, said throat having a circumferential width which is a minor part of the circumferential width ci each tooth, whereby thejchips formedy -by each cutting edge are trapped in the passagelead-ing inwardly therefrom.

1.0. A milling cutter for removing a met-'alf laver from a workpiece to form a surface thereon by relative feeding movement `between the rotating cutter and the workpiece, saidl cutter comprising, in combination, a cylindrical body, .an annular series of circumferentially spaced teeth pro- .iect'ing from the end of said 'body a distancerto permit of .chip ow radially =and inwardly' between saidv Work surface and said! bodyend', a side Von each tooth facing. outwardly and' having a cutting edge along the leading edge,l a cutting face .on `each `tooth `,positioned to induce the chips formed .by said, edge to new inwardly toward .the cutter axis, and a .third ,side on each tooth converging inwardly toward thecuttingcface and cooperating withvthe Acutting face of the succeeding 1tooth .to define an inwardly Haring ,chip passage having a narrow `entrance for receiving 2,33 3,4553 and being spaced .from-the ,apex `of the precedingthe chips formed by 1one of said Kcutting edges,l and an end surface on said body .defining the top of said chip passage anddive'rging radially inwardly away from the work ,surface whereby to provide for ,inward flaring ,of the passage in `a second direction.v 'Y 1 j y g y ll. A milling cutterhaving, in combination, ay ,rotatable body, annular series ofA Ibladesof genelal-ly equilateral triangl-ilary ,cross-sections mounted on said body ,for endwise adgiustment with one side loi each triangle facing radially outwardly :and with ythe blade .ends projecting from one ien-,d of said body `al distance such as to permit of the inward ,now of chips between the bod-v end and said work surface, and aside cutting edge formed on -each of .said blades at the junction of said outwardly i'facing side and the adiacent :secondfsideof thetriangle willich-donnes the cutting face of the blade and which is positioned to induce the chips ,formed by said Acuttingy edge to naturally Vflow inwardly and enter the throat' of the inwardly flaring chi-p .passage tor-med :by .the cutting vface 'and `the :thi-rd side of theprecedin-g blade, theadjacent blades'be'ng inclined at d-iierent angles relative to the vplane of Acutter rotation so aste permit-of closespacing of said projecting ends andthe formation ofv saidy chip passages with ,narrow throats;Y 4

l2, A milling cutter for removing a metal layer from :a workpiece toform a surface' thereon by relative feeding movement between the rotating cutter and the" workpiece, said cutter comprising, in combination, a cylindrical -body having a coned endi surfaceLd-iverging zoutwardlyalong thevaxis of thev body, annular series of. circumferentially spaced teeth Jprojecting vfrom saidcone end surface whereby the latter surface provides for radial inwardaiiingpot the chip' passages defined between' ithefadjacent lfteeth,` and cutting; edges' formed? on said teethf .for removing chips :and directing the: latteryinwardly:along` saidl passages toward fthe cutter-axis. f 1'3. Avmilling cutter' having, in combination', -a cylindfrlic'allf"bodfyv having circumferentially span'ed holes` extending 'longitudinally of the lbody axis and opening atone end' of the body in-single' annular series'and at `the other fend' in a-plural'ity' of concentric'- spaced annular' series, and a, blade mount'edjin each hole-forendwise Vadjustment 'andl havingvv one end projecting from saidvnrst mentioned end of said' body to fonn a cutting tooth, said blades being of generally triangular cross-section having one side facing outwardly from the' cutter axis .wherelzpy the othersides of the adjacent projectingxends denne chip4 passages diverglng,radially'inwardly CHARLES E. KRAUS. 

